Process for treatment of olefincontaining mixtures



G. C. BAILEY July 9, 1946.

PROCESS FOR TREATMENT 0F'OLEFINCONTAINING-MIXTURES. 1

Filed octfso, 1941 'aoivavdas -azl mv On.

f2 Y .ov mm other types of mono-olefins.

Patented July '9, 1946 y PROCESS FOR TREATMENT F OLEFIN- CONTAINING IVIIXTURES Grant C. Bailey, Bartlesville, Okla., assignor to Phillips Petroleum Company, V,a corporation .jof

Delaware Application october so, 1941, serial No. 41");,301

This invention relates to the catalytic polymerl ization of olens, and more particularly it re-Y lates to the polymerization of selected Aoleiins contained in a 'hydrocarbon mixture. It further relates to the production of an optimum yield of f stock from a. mixture of superior lubricating oil low-boiling olefins.

The catalytic polymerization of olefins to compounds of higher molecular Weight is well known. Charge stocks for such processes are preferably mono-olefins, and include normally gaseus or liquid olens prepared by dehydrogenation of parafns, dehydration of'alcohols, cracking or dehydrogenation of waxes or gas oils, etc. The olens may be used either singly or mixed with other olens or inert diluents. The reactions may be effected over a wide range of temperature, but usually in the range `of from "-301F. to 200 F. The active metal halides are preferred as catalysts such as aluminum chloride, zirconium chloride,`boron fluoride, and the like, used either alone or in combinationv with'various modiers such as are well known, including inorganic materials such as sodium chloride and. organic materials suchas ketones, etc.

Inpolymerization reactions, as briefly outlined above, oils may be obtainedhaving widely varying characteristics, depending markedly on both the olefin charge and the properties and conditions of the polymerization system, In practice, the charges used for the preparation of oils fre'- quently contain a wide variety of olen reactants, even though one type may be 'in predominance. e

Metal halides of the Friedel-Crafts type such as boron uoride and aluminum chloride, generally polymerizeolens at a rapid rate. For example, when aluminum chloride is added to liquid isobutene at temperatures above about 0 F., the reaction proceeds with such rapidity that it is difficult to maintain the temperature of the reaction mixture at a constant value. Polymerization reactions using phosphoric acid type catalysts usually proceed much more slowly. Still l 4 Claims. (Cl. ZBO-683.15)

yl-l-pentene, Z-methyl-2-pentene, 3-.methyl-2A- pentene and the like. y l

The rate at which mono-oleins are polymer- V ized is also to some extent a function of the mo- 'prising leculary weight of said olens. In general," the higher molecular YWeight olens polymerize `less yrapidly than the lower molecular weight olens.

Thereare, however, exceptions to this generalization, one of the most outstanding being ethylene whichr is polymerized with diiliculty even by aluminum chloride catalyst. .I

Insome polymerization proCSSSes'it has been found that when a mixture of olens is to be polymerized to form lubricating oil stocks, high yields of desirable products are rapidly obtained by first removing substantially all of the tertiarybase olei'ins and then polymerizingnontertiarybase clens in the presence of a suitable catalyst to produce polymers suitable Afor use as lubricating oil stock. The most desirable polymers suitable for use as a lubricating cil stock are `produced from the polymerization of individual nonvtertiary-base l-olens. f

.selectively 'polymerizing tertiary-base olefins which are present in a hydrocarbon mixture comalso nontertiary-base mono-olefins. More specifically I have found a catalyst material that will polymerize tertiary-base olens,

-such 'as isobutene, without'promoting appreciable polymerization of, other types, of mono-olefins such as nontertiary-base mono-olens, that `may bepresent in a hydrocarbon mixture. Such catalyst material comprises a tin tetrahalide, preferably in conjunction with a stabilizer, such as will be discussed hereinafter. As a tin tetrahalide catalyst I include mixtures of tin4 tetrahalides, vsuch as a mixture of tin tetrachloride and tin"tetrabromide, and "also mixed tin tetrahalvrchloride, tin bromotrichloride, and the like.

other catalysts such as those comprisingsilica gel may require specific Yconditions of somewhat higher temperature and pressures to polymerize olens atan appreciable rate.

In general, mono-oleiins having the tertiarybase structure polymerize more rapidly than By tertiary-base olens I intend to include, in general, such'ole'- ns which correspond to the formula `R2C=CRK2 where each R is an alkyl group and each R is `hydrogen or any alkyl group. Such olens, up-

on hydrolysis in an acidic medium, will generally yield a tertiary alcohol. Typical' low-boiling tertiary-base oleins are Z-methyl-propene,

Z-methyl-ll-loutene, Z-methyl-Z-butene, 2:-meth- L nontertiary-baseV mono-olens.

ides, such astin tribromochloride, tin dibromodi- One object ofY this invention is to selectively polymerize olelns.

Another object of this invention is to polymerize only tertiary-base olefins in awhydrocarbon mixture containing tertiary-base oleflns and Another object of this invention is to produce a lubricating oil base stock having superior qual.- ities from low-boiling oleiins.

Still another object of this invention is to provide a superior catalytic conversion system-for 'the production ofV desired oils fromolens.

A further object of this invention is to purify an' olefin-containing mixture in such a manner that undesirable materials, such as tertiary-base olens and/orv compounds containing reactive oxygen, sulfur, nitrogen, and the like, are removed. l

f' Other objects and advantages of my invention will be apparent from the accompanying disclosure and discussion.

Tin tetrahalides such as tin tetrachloride and tin tetrabromide have been classed by other workers in the art as active metal halide catalysts and as Friedel-Crafts type catalysts, along with aluminum chloride, aluminum bromide, boron iiuoride and the like. I have found, however, that the tin tetrahalicles dier fundamentally from such catalysts in their polymerization characteristics; Aluminum chloride, aluminum bromide, boron fluoride and the like readily polymerize nontertiary-base mono-olens such as propene, butene-l, butene-2, pentene-l, and the like. Hereinafter, such catalysts will be termed metal halide catalysts which are active for the polymerization of nontertiary-base olens. However, tin tetrahalides, such as tin tetrachloride and tin tetrabromide, do not polymerize such compounds to any detectable extent under the reaction conditions which form a part of my invention, but only polymerize tertiary-base oleiins, such as isobutene, as will be clearly shown hereinafter. neither n-pentene-l, n-pentene-2, n-hexene-l, nor n-octene-l can be polymerized in the presence of a tin tetrahalide at a temperature equal to or below the boiling points of said compounds at atmospheric pressure, although at the higher temperatures halogenation reactions appeared to take place. My invention is based, therefore, upon the discovery that tin tetrahalides, per se, are completely selective in their catalyzing action for the polymerization of only tertiary-base olens under the reaction conditions which form a part of my invention, and not upon determining conditions at which a known polymerization catalyst will promote the polymerization of tertiarybase olefins sufficiently faster than the polymerization of other oleflns that a selective polymerization vmay be accomplished. Furthermore, I have found that tin tetrahalide catalysts do not appear to promote copolymerization reactions between tertiary-base olens and other mono-oleins, so that tin tetrahalide catalysts may be used to decrease the content of tertiary-base olefins in a Vmixture without concomitantly decreasing the content of other mono-olens. It is a characteristic of catalysts such as aluminum chloride, boron fluoride, zirconium tetrachloride and the like, that in the polymerization of oleiins the reaction is promoted by the presence of the corresponding hydrogen halide or a compound that produces hydrogen halide under the conditions of the reaction, such as water or tertiary butyl chloride. ganic nitro compounds, ketones, ethers, and the like, have little or no apparent effect and in some cases may even have a tendency to lower the reaction rate. I have found that tin tetrahalides, particularly tin tetrachloride and' tinl tetrabromide, when used as catalysts in olefin polymerization reactions show unique response to added modiers. As an illustration, when a tin tetrahalide comprises the catalytic material for facilitating the polymerization of olefins, the presence of hydrogen halide actually inhibits said reaction. This is in direct contrast to the action exhibited by the presence of a hydrogen halide in the presence of an aluminum chloride type of catalyst for a similar charge stock. Also, when passing isobutene for example, in intimate contact with a tin tetrahalide, such as tin tetrachloride at atmospheric pressure and room temperature, said isobutene is rapidly polymerized with @Volutlon For example, I have found that Y Other types of modifiers, such as or- 4 of heat. However, the reaction rate gradually decreases with a concomitant separation of a light amorphous precipitate, apparently a complex stannous compound. The activity of the catalyst for such reactions can be increased and maintained for a prolonged length of time by the use of selected organic stabilizers. Such stabilizers include nitro hydrocarbons, such as nitromethane and nitrobenzene, and ketones having an alpha carbon atom to which is attached a single hydrogen atom, such as methyl-isopropyl ketone, diisopropyl ketone, and isopropyl-phenyl ketone. Other types of ketones, such as acetone, acetophenone, benzophenone, and cyclohexanone, do not act as stabilizers for the reaction.

Relatively large proportions of such organic stabilizers are necessary to influence the polymerization rate in a positive manner for a suitable period of time. For example, in the polymerization of isobutene ,at room temperature, and atmospheric pressure using'tin tetrachloride catalyst, it was necessary to add 0.1 mole per cent of nitrobenzene, based on the number of moles of tin tetrachloride in the systenrto obtain appreciable stabilizing action; this was efective for only a short time. In contrast, the addition of 65 mole per cent of nitrobenzene on the same basis not only accelerated the polymerization but maintained the catalyst activity at a constant value for a prolonged period oi time.

Although it may be that the factors which result in eventual decrease in activity when a small amount of stabilizer is present will eventually cause deactivation of catalyst even when a larger amount of stabilizer is present, it is to be appreciated that the actualfactors which affect the system containing catalyst and stabilizer are not yet'completely known.

When producing products within the conventional lubricating oil range it is desirable that such products haveviscosities ranging from about seconds at 160 F. to about 2Go seconds Saybolt viscosity at 210 F. although oils above and/or below this range may be useful for special purposes. The molecular weights of these desired products are normally greater than about 300 and less than 800, and generally they are less than 500, although products somewhat either side of these-limits may at times be found desirable. The primary product of my process is a simple olefin polymer, having one double bond pe'rmolecule, and for use as a component of lubricating oil it is generally desirable to increase its stability toward oxidation, as by nondestructive hydrogenation. The hydrogenated or unhydrogenated produ-ct may be used as a lubricating oil as such, or may be blended with various other stocks to produce a composite lubricating oil. In some instances my process may be operated to produce olenic products from the tertiary-base olefin polymerization and/or the nontertiary-base mono-olefin polymerization of somewhat lower molecular weight than that suitable for direct use as lubricating oil, and such olefinic products may be employed to alkylate aromatic hydrocarbons, such as benzene, or toluene, or their derivatives,-to form hydrocarbons of suitable molecular weight and viscosity characteristics having also enhanced solvent characteristics and the like. Olenic products suitable for such additional treatment are included, along with products suitable for direct use as lubricants, in the broader consideration of my invention, and are to be included in the term lubricating oil stocks.

According to thisinvention. a mixture containingtertiary-base-and nontertiary-base mono-y olenssis treated with a tin. tetrahalide, such' as tin tetrachloride or 'tin tetrabromide, preferably in admixture with, a stabilizer, as is described herein, at a temperature in a' range of about 30 to v212 F. and at a'pressure at which said olefin mixture is'v inthe liquid state. Tin tetrachloride and tin tetrabromide are very soluble in hydrocarbons andunder the conditions oftreatment the system is homogeneous and thevr reaction' takes place inv a single liquid phase.V Thereaction is exothermicr and suitablemeans ofagi'tation andcooling shouldbe provided for optimum results. By this treatment substantially only vtertiary-base jolens. are selectively converted to polymers, Vthe lowest. boiling ofrwhich'isr :diisobutene having a boiling point of about 215A to 2210" F. By conducting the.` polymerization' at about room temperature, only a small. proportion of isobuteneY polymer will consist of dimer..l The remaining nontertiary-base mono-olens maybe separated fromjthe reaction mixture by distillation, absorption methods, or any Aother means known to the art.. Before a separation step, such as distillation, it may bey desirable to remove tin halide catalyst, such as` by extracting with cold water followed by filtration *using an adsorptive clay filter aid,i especially when the catalyst is tin tetrachloride. In some cases tin tetrahalide may be separated and' purified in such a manner that-itA may be recycled Vto treat additional mixtures containing olen hydrocarbons. f f' Besides promoting the removal of tertiarybase mono-olens from mixtures containing such olens, I have.' alsov found that tin tetrahalides can be used to separate di'olefins,` reactive organic oxygen-containing compounds, reactive organic sulfur compounds, and the like from mixtures containing such ycompounds and nontertiary-base `mono-olelns without appreciably aiecting the nontertiary-base` mono-olens. Such a separation isaccomplished by converting diolens, reactive organic oxygen-containing compounds and reactive organic` sulfurV compounds intol higher molecular 4weight compounds in the presence of a tetrahali'cle catalyst, these compounds oftenv being insoluble. in the unreacted hydrocarbon material'. y

When the material that is being treated' by a tin tetrahal-ide isv essentially a hydrocarbon mixture containing tertiary-base olefins and nontertiary-base mono-olefinsv and no appreciable amount of diolen's andwhen the-tertiary-base olefin content of said mixture issubstantially pure isobutene, polymerization at room temperature and sum-cient pressurev to result in a liquid phase will produce an appreciable proportion of polymer in the viscosity range of lubricating oil'. On separation of this oil from the remainder of the mixture, such as by fractionation, an oil fraction is obtained having a relatively high viscosity index, higher than the viscosity index of a fractionk of similar Viscosity obtained by polymerizing substantially pure isobutene using aluminum chloride catalyst. Y

Removal of tertiary-base, Aolens from .a mixture containing them is readily accomplished fins.. I'he catalystand stabilizer,v are-so chosen that: theyV canbe satisfactorilyremoyecl from vthe reactionjmixture `Without interfering Awithisubsequent usage of any other desirable compunentzof the reactionmixture. Usually Y,both catalyst and` stabilizer'. are removed kby extraction methods. based 4on their own physicaland/ox: chemical, properties,l as will he readily" appreciated by oneskilled in theV art..

' Whena mixtureto be' treated. according to my invention containsr hydrocarbons having ai comparatively wide range of molecular weightsizfor example from' 3 tof16 carbon. atom'sxpermolecule, it is evident-that after a treatment .witha tin tetrahalide there may be van appreciable ramount of tertiary-base `oleiinpolymers withinl this molecular weight. range., Such a situation-may be undesirable and' .often should? be gavoided. This can be accomplished in mostl instancesfby separating such a mixture into fractions` of narrower boiling range and treatingfeachffraction separately.Y However, in'k specificcasess special techniques may produce thenesired rel sul't. For example, a mixture contai-ningessentially olefin and'some-parai-n hydrocarbpnshav; ing 6 to `16 carbon atoms per moleculefwas subjected to polymerization conditions to form products Yin the viscosity range oi'VV lubricating oils. The mixture comprisedfprimarily straight chain mono-olens but contained su-,mci'ent tertiary-base Yolefins, di'olefms, bXygenw-containing compounds, and Vthe/like that polymerization usingy zirconium tetrachloride: plus "hydrogen chloride promoter produced an oil havingvan unsatisfactorily low viscosity index. 1 When the? mixture-was first Vtreated'y with tintetrachloride together withf'd-iisopropylketone at a temperature ofabout 175 to 210'Fiy and sufcient pressure to Yallow liquid phase'y operation, thepolymers produced were almostentirely'below `thel molecular weight' range of lubricating oils. Also, the tin tetrachloride reacted with undesirable compounds to form a precipitate. The reaction mixture was cooled, filtered and the catalyst removed by the extraction with cold water. The purified eluent which stillu contained a small amount of diisopropyffketone was subjected to polymerization condi-tionsusi-ng zirconium tetrachloride in the presence of hy"- drogen chloride. The product in the lubricating oil range from this polymerization possessed a high viscosity index. The tertiary-base, olen polymers in the charge to the zirconium tetrachloride polymerization step had only'l a slight tendency to polymerize further to lun'icat'i'ngJ oil range product. Such polymer" was therefore easily separated from higher boiling" material by fractional distillation. Y

Ideally, all tertiary-base Aoleflns in av mixture treated with a, tinV tetrahalide are polymerized and all nontertiary-base mono-ol'efirisy areunchanged. Actually', such complete conversion of tertiary-base olens is often impracticable and unnecessary. The deleterious effect of the presence of tertiary-base olefins inthe subse-, quent polymerization of nontertiary-'base monooleiins is Aroughly proportional tothe concentration of the tertiary-base olens-softhat in some cases essentially complete frenio'valj lis necessary, while in others economic considerationsfmay'permit as much as several! per cent of theremaining olelinicf material tobe tertiary-base olens;

VWhen it is stated that vol'eiinic material is freed o f its content of tertiary-base 'olensg 'suchfactors should be taken into consideration.

It is preferred that the conversion of tertiarybase oleiins according to my invention be carried out inthe liquid phase, and while higherv pressures may-be used where an additional advantageous effect resu1ts, generally a pressure sucient to maintain an initial liquid phase will be found sufficient. With low-boiling olens it may be desirable to include a high-boiling inert diluent to aid in forming and maintaining a liquid phase under relatively low pressures. Generally paraiiins and cycloparafiins are best suited for such-use.

The reaction time for polymerizing tertiarybase olens in the presence of a tin tetrahalide varies over a wide range depending to a great extent upon the amount of'tin tetrahalide catalyst employed in the polymerization step and on the temperature. For example, when the catalyst comprises 10 to 20 weight per cent of the reactant material, a reaction time within the range of thirty to fifty minutes at room temperature and under sufficient pressure to result in liquid phase conditions will produce desirable results. However, under the same conditions except that the vamount of catalyst is only about 2 to 5| weight per cent of the reactant material, a reaction time as high as six hours is not uncommon for producing desirable results. The reaction time is lowered by an increase in the temperature employed for the polymerization step.

A tin tetrahalide employed as a catalyst in my process is preferably soluble under the reaction conditions and when a tin tetrahalide catalyst isV employed which is normally solid within the temperature range disclosed herein for operating my process, usually a suilcient amount of it can be dissolved in the material being treated to promote the reaction.

The reaction temperature for conducting the conversion in the presence of a tin halide may be chosen within a rather wide range. Higher temperature promote a rapid polymerization but gen-- erally lresult in a, product of lower molecular weight. A suitable temperature for any particular case may readily be determined by trial, by one skilled in the art, in the light of the present disclosure, and will generally be found in the range between about 0 and about 240 F, A preferred range is between 30 and 200 F.

AThe use of tin tetrahalides for the separation of olens in the manner described is not limited to any specific embodiment because it is evident that the details of such a process will depend upon,y among other things, the nature of the charge stock and the use that is to be made of the nal products.

My invention will now be illustrated in connection with the accompanying drawing which shows diagrammatically one arrangement of apparatus by lwhich my invention may be practiced.

A hydrocarbon mixture containing both tertiary-base and nontertiary-base mono-olei'lns is introduced to the system through conduit I0 controlled by a valve II to polymerization unit I2, whereiny the mixture is treated with a tin tetrahalide catalyst, preferably -tin tetrachloride or ti'ritetrabromide, which acts as a catalyst for the selective polymerization of tertiary-base olens. Such a catalyst may be conveniently admitted to polymerization Zone I2 with the incoming feed stock or; separately through conduit 49, controlled by a valve 50. A stabilizer for said catalyst selected from the group consisting of nitro hydrocarbonsand ketones having an alpha carbon atom to which is attached. a single'hydrogen atom may 8 be added to the polymerization zone with the tin halide through conduit 49, or separately through conduit 39 controlled by a valve 40. vThe polymerization is preferably carried out under conditions suitable to produce low-boiling polymers, such as aresuitable for use as motor fuel or as motor fuel stocks, or such as to produce polymers suitable for use as lubricating oil stocks, as previously discussed herein. The polymerization zone I2 vwill consist of suitable polymerization units together with heaters, coolers, catalyst chambers, and the like known to the art.

When the hydrocarbonmixture to be treated according to my invention contains tertiary-base and nontertiary-base mono-oleiins within a wide range of molecular weights it may be desirable to pass such a mixture through. conduit I3 controlled by valve I4 to a separating meansV I5 from which a selected fractionof narrow boiling range or narrow molecular weight range is removed through conduit I6 controlled by a valve I1 and passed tothe polymerization zone I2. Material removed through conduit 20 controlled by Valve 2I may be further separated into other narrow boiling range fraction and each fraction subjected to individual polymerization conditions which are optimum for polymerization of substantially only tertiary-base oleiins in the presence of a tin tetrahalide. Often, however, it will be unnecessary to separate such a mixture into several fractions when desirable results can be obtained by treatment of such a mixture in a single zone under conditions suitable for the polymerization of tertiary-base olens contained therein.

The eiliuent from the polymerization zone I2 containing unr'eacted nontertiary-base mono-olens passes through pipe 22 and valve 23 to separating means 24. In separating means 24 unreacted non-tertiary-base olelns are separated from polymers produced in unit I2. These polymers may be removed with or without separation into various fractions, through suitable means represented by a conduit 25 controlled by valves 26 and 11. When these polymers, -or a fraction thereof, are suitable for use as a lubrieating oil stock, such material may be passed from conduit `25 through conduit 10 controlled by a valve 28 for blending with a lubricating oil stock produced i'n a subsequent part of the process, as will be described. However, when the charge stock to my process contains some diolens, reactive oxygen-containing compounds, reactive sulfur compounds and/ or other gum forming material as well as tertiary-base olefins, other high-boiling material will be produced besides that from tertiary-base olefins. When this is the case, a mixture containing such higher boiling material is removed from separator 24 through conduit 25 and valve 2B and at least a part or all may be discharged from the process through valve 11 or passed through conduit 'I2 controlled by valve 13 to separating means 14. In separating means 14 desirable polymers produced from tertiary-base olens may be removed through conduit 21 controlled by valve 'I8 and passed to conduit 10 for blending as herein described. Undesirable high-boilingv material can be removed from separating means 14 through conduit 'I5 controlled by valve 16. High-boiling material removed through valve 11 may be Vtreated in such a manner as appears desirable. For example, ter-Y tiary-base oleiin polymers so removed may be passed to a catalytic alkylation step to react with parailin` hydrocarbons for the production ofhighly branchedhigher boiling paraffin hydrocarbons of superior antiknock quality, and suitable as constituents of motor fuel. Various alkylation catalysts such ashydrofluoric acid, sulfuric acid,. aluminum chloride, silica alumina, .and the like may be' employed in Vsuch a step. l

A material containing Vvnontertiary-base monooleflns and substantially free of tertiary-base olens,.as herein discussed, is passedfromseparating means 24 `through a conduit 3| controlledv by a valve 29 to apolymerizationunit 33 wherein la polymerization is eected to form vpolymers suitable for use as a lubricating oil stock. The olei'lns polymerized in unit 33 may be supplemented by nontertiary-base mono-olehs added to the system through a conduit 30 controlled by a valve 32 passing to conduit 3|, `and in some instances olei'lns so added mayconstitute the sole source of olelinic material charged to this step. Polymerization in unit 33 is carried. out in the presence offacatalyst active for the polymerization of nontertiary-base olefLns, such as aluminum chloride, zirconium chloride, boron fluoride or other halides of aluminum, zirconium and boron associated with a hydrogen halide which maybe addedthrough a conduit 31 controlled by a valve 38. However, it is to be understood that such catalysts are not to be considered as equivalents to one another, either in regardrto polymerization conditions or characteristics of products formed.. The polymerization conditions are such that al1-,optimum yield o-f rpolymers*suitable for use as .a lubricating oil kstock are produced as previously has been discussed, and the unit 33 -will lcomprise suitable catalyst chambers, heaters,

coolers, pumps, and the vlike as Vmay be supplied for any particular case by, one skilledrin the art.

The eiliuent of unit 33 passes througha conduit34 controlled by a valve 35 to separating mea-ns36 vand when the material passing through conduit 34 consists substantially only of hydrocarbons, the fractions recovered from the material may be separated by simple fractional dis'- tillation and one or more fractionating columns as'may be readily ascertained by one skilled in fthe art. In some instances when a mobile polymerization catalyst is used in unit 33, separating means36 may also Vinclude suitable equipment for removal of the catalyst and any impurities contained in the material passing through conduit 34 as may be suited .to the particular material being treated. Unreacted olens and/or .lowboiling polymers may be removed from separating means 36 `through a conduit 4| controlled by a valve 42 and returned for further reaction in unit 33 by conduits 3U and 3|. Undesired lowboiling material, which may include paranins, is discharged from the system through a conduit 43 controlled by a valve 44. Heavy hydrocarbons, tar and/or sludgemaybe discharged from the system through a conduit 45 controlled by a valve 46. One or morefpolymer fractions containing polymers suitable for use as lubricating oil stock are recovered from separating means A36 through one or more conduitsk illustrated by conduit 41 and may be discharged from the system through valves 52 and 53. f p

As previously discussed it isgenerally desirable to subject such polymers to further treatment which may include alkylation with aromatic hydrocarbons, saturation with hydrogen by nondestructive hydrogenation, or the like. Such further treatment will be illustratedby nondestructive hydrogenation and whensuch treatment is desired, anypart or all of a polymer fraction suitable for allubricating oil` stock Ymay vbe trolled' by a valve 48 toa hydrogenator 54 wherein/a major part of the polymerfractionl is nondestmctvely yhydrogenated .in the presence of a suitable hydrogenation catalyst and. in the presence of hydrogen added lthrough conduit. 55 controlled bya valve 56. A resulting saturated 'hydrocabon material is passed through conduit 51 controlled by a valve 58 toseparating means 6|. lll-saturated` `hydrocarbon* material suitable for use as a lubricating oil stock may be recovered fromv 4separating v,means'tl through conduit 62 controlled byy valve :63 and anyj vundesired material maybe discharged from the system through aconduitid cont-rolled'bya valve 65. When the polymerization in unit |2 Vis such a to produce polymers suitable for use as lubricatingpolestoclc, such polymers ymay be blended with polymers: producedinunit 33 to forma compos-.I ite product of the ,two :types ofY polymerization. When.-r arpolymer fraction fromunit |2 is recovered without. additional treatment, a polymer fraction passing throughconduit 10 and valve 28 Ymay Vbe'passed Ythrough valve 1| to conduit 41 and the `composite lubricating oil stock recovered vthrough valve 53,. When it is desired to subject polymer passing'through conduit .10 to subsequent hydrogenation, such polymermay be removed from conduit 1|!4 through a conduit 66 controlled by a valvev 61Y andpassed` to conduit 5| and hydrogenator 54 for further treatment as previously discussed. .Y A

It 'is to be appreciated that the drawing just described is diagrammatic only. The various pieces of equipment illustrated and discussed are` conventional in nature, and in any application of my invention there will be associated with the individual units shown various pumps, heaters, coolers, reflux accumulators, heat exchangers, fractionating columns, temperature indicating and control devices and the like known in the art and which may be suitably supplied for anyfparticular case by one .skilled in the art following the teachings of the reaction conditions and material flows disclosed and discussed herein.

My invention will be further illustrated by the following specific examples, which show various advantages of the invention but which are not necessarily to be construed as hunting the'invention. Y

EXAMPLE I f Y Isobutene was passed in contact with approximately parts by weight of tin tetrachloride at roomtemperature and atmospheric pressure at` the rate of about 25 vparts by weight per hour.

The isobutene was bubbled through the body of EXAMPLE II The run cited in Example I conducted at room temperature was repeated. When the activity of 1 1 the catalyst had decreased considerably, 0.1 mol per cent oaf nitrobenzene Was added. The catalytic activity was increased only for a short time. Sixty-live mol per cent of nitrobenzene Was then added. During an eight hour reaction period, the catalytic activity did not decrease noticeably. The stabilizing effect of nitrobenzene was thus evident.

EXAMPLE III The run cited in Example I conducted at room temperature WasV repeated using as catalyst tin tetrachloride plus 50 mol per cent of diisopropyl ketone. Isobutene was bubbled into the catalyst mixture for 22 hours. The reactionV rate decreased only slightly throughout the entire reaction period.

- Y 'EXAMPLE IV The run in Example I conducted at room temperature was repeated using as catalyst tin tetrachloride plus Y50 mol per cent nitromethane. The reaction was continued for eighteen hours. The activity of the catalyst vdid not noticeably decrease duringA` this period. The temperature increased to a maximum of 104 F. during the experiment. About 24 per cent ofthe resultant polymer was in the viscosity range of lubricating oil. The characteristics of two fractions are given in Table I.

The run cited in Example I conducted at room temperature Was repeated adding each of the following materials: carbon tetrachloride, tertiary butyl chloride, hydrogen chloride, water. None ofY these promoted the polymerization of isobutene, and they may actually have hastened the deactivation of the catalyst.

EXAMPLE VI Tin tetrachloride and liquid propene were sealed in a glass tube in a Volume ratio of ,1:15. After standing four days at room temperature, no polymer Was formed.

EXAMPLE VII The run cited in Example I conducted at room temperature Was repeated using tin tetrachloride plus pentene-l. No polymervvas produced. This run was repeated adding each of the following compounds: carbon tetrachloride, tertiary butyl chloride, water, nitromethane, and diisopropyl ketone. YNo polymer Was obtained from any of these runs. Y Y

EXAMPLE VIII The olen li-methylpentene-Z was not polymerized at room temperature using tin tetrachloride catalyst either alone or with stabilizersv such as employed in Example VII.

EXAMPLE IX- An oleiin-containing charge stock boiling between 122 and 167 F., obtained from thermal conversion of low-boiling hydrocarbons, was polymerized With al catalyst consisting of aluminum chloride plus hydrogen chloride promoter in liquid phase at. 86to95Vv F. The catalyst was rapidly deactivated With the formation of a darkcolored insoluble residue. The resulting polymer fraction in the lubricating voil viscosity range possessed viscosity indexgvalues of 10 to 35. t

Another portionof this stockwas treated with 10 per cent by weight ,of aV tin Ytetrachloridenitrobenzene mixture vat F; for aftwo hour period.` The unreactedolen-parain constituentswere separatedby distillation; .It was found that about 20 per cent ofthe total olen content of the charge Was removed in this treatment. The remaining olefin-paraffin mixture in the'.,122 to 167? F. boiling range was treated with aluminum chloride plus hydrogen chloride promoterin liquid phase at`86 to 95 F. Only a small'proportion of dark-colored sludgeV Was formed Aduring polymerization. Theresulting polymer fractions'in the lubricating oil viscosity range, which were equivalent in volume to those produced `in the preceding experiment.' possessed viscosity index values of 40 to 65.r The tin tetrachloride treatment thus removed from the olefin-containing charge stock materials which adversely affected the activity of the aluminum chloride catalyst and also materials which produced low viscosity index polymers.

Iniview of many possible modifications of the process that will be obvious to those skilled in the art, the invention should not be limited unduly by the foregoing specication and examples, but it should be understood to ber extensivein scope and equivalents, Within the limits of the appended claims, Without departing from Vthespirit of the disclosure and teachings. t

I claim:

1. In a process for the selective polymerization oftertiary-base oleflns which are associated with nontertiary-base olens, the improvement which comprises subjecting a liquid hydrocarbon mixture which contains such olens to the polymerizing acton'of a tin tetrahalide associated with a ketone in which there is an alpha carbon which has a single hydrogen to polymerize only tertiarybase olens, and recovering from said polymerization a hydrocarbon mixture which contains unreacted nontertiary-base oleflns and is substantially free Yfrom tertiary-base olefins.A

2.v In a process for the selective polymerization of tertiary-base olens which are associated with nontertiary-base olens, the improvement which comprises subjecting a liquid` hydrocarbon mixture which contains vsuch olens to the polymerizing action of a tin tetrahalide associated with diisopropyl ketone vto polymerize only tertiarybase oleiins, and recovering from said polymerization a hydrocarbon mixture which contains unreacted nontertiary-base olens and is substantially free from tertiary-base olens.

3. A process for the polymerization of tertiarybase olens whichY comprises subjecting such olens to the polymerizingaction of a tin tetrahalide associated with a ketone in which there is an alpha carbon atom to whichV is attached a single hydrogen atom. v

- 4. A process according to claim 3 wherein said tin tetrahalide is tin tetrachloride and said ketone is diisopropyl ketone.

GRANT C. BAILEY. 

